Process and apparatus for producing laminated paper tubes



Nov. 6, 1951 c. B. HEMMING 2,574,329

PROCESS AND APPARATUS FOR PRODUCING LAMINATED PAPER TUBES Filed Sept. 22, 1945 2 SHEETS -SHEET 1 7 INVENTOR. 1

BY 6fifif/6j B.

Nov. 6, 1951 c. B. HEMMING PROCESS AND APPARATUS FOR PRODUCING LAMINATED PAPER TUBES Filed Sept. 22, 1945 2 SHEETS-SHEET 2 INVENTOR. Car/aflfiwmzgo BY I Z Z A19}.

w Ilrl n H Mw ww n u 1:11:11 I I I I I i: 5 lfl Q HI." I mn .3 HI w M M AE Q 1 v 5 on mm mm Patented Nov. 6, 1951 PROCESS AND APPARATUS FOR PRODUCING LAMINATED PAPER TUBES 'Charles B. Hemming, New Rochelle, N. Y., as-

signor to United States Plywood Corporation, New York, N. Y., a corporation of New York Application September 22, 1945, Serial No; 618,036

This invention relates to process and apparatus for producing and curing paper tubing. It relates more particularly to the production and curing of thin-walled phenolic impregnated paper 12 Claims.

cally on bolts 33 and 34 in supports and 6. A solid shaft or roller 31 is journalled in apertures 38 and 39 near the ends of the pressure members 35 and 36, so that its outer surface is tubing of the laminated type that is made up of 5 flush with or extends slightly beyond the outer a number of convolutions. curved ends 42 of pressure members 35 and 36,

In carrying out the invention paper is im- Fig. 5. A straight rigid hollow tube or mandrel pregnated with a resin, the impregnated paper 40 is journal at One end in the Opening 29 in is wound upon a hollow metal mandrel which is ear ng 28 and at the other end in the bearin heated electrically While the paper is kept tight 30. -A rOW o perforations 0 p gs 4| is proon the mandrel so that the paper tube is cured vided through the wall Of the tube 40 between very quickly. the bearing 28 and opening 30.

The inventio may b nd t d from th d An electric transmission line 44 is connected scription in connection with the accompanying y leads d Switch 46 t0 the primary f drawings in hi h .5 transformer 58 of which the secondary 49 is con- Fig. 1 is a plan view of an illustrative embodinected to the extensions 2| and 22. ment of the invention in which some of the parts A mete! 53 s eenneeted t h switch 5| to are shown somewhat diagrammatically; line 34. This motor drives pulley 52 through Fig. 2 is a section along the line 2-2 of Fig. 1; pp d p y 3 a d b s 5 as indicated.

Fig, 3 is a section along the lin 3 3 of Fig 1; A hose 55 from a vacuum source, not shown, is

Fig. 4 is a longitudinal section on an enlarged attached to the right hand end of the be 0, scale along t line 4 4 of Fig 1, and this hose being inserted into opening 3| in the Fig. 5 is a section on an enlarged scale showing pp The hose y rotate With e mans of th parts drel through a universal connection with the Reference characters 5 and 6 indicate supports :38 source of vacuum, or may remain stationary and or upright members having anchoring means I y the mandrel revolve A Sheet of P p 55 and a t keep th Supports 5 and 5 in place of the sort described below, is wound upon the Th anchoring means 1 and 3 are provided mandrel so while this mandrel is heated as dewith flanges H and 12 t t extend into grooves scribed above, and also while the pressure mem- I3 and m in t supports 5 and 3 supports 5 bers and 3B and roller 3! keep the paper pressed and Hi are provided on the upright members 5 so that the convolutions e tightly w d and and 6. Electrical contacts I! and I8, respectively, the heat in the tube mandrel causes the are pivotally supported on screws I9 and 20 which CQYIVOIHtiOnS to adhere closely to make a be are tt to the supports 5 and g Extem with solid wall structure. In certain instances, sions 2i and 22 are provided on the contacts I! 35 the mandrel Will cold When the paper is and 18 for convenience in making electrical con- Wrapped on it and W111 be heated b equently. nections Bolts 23 are provided for keeping the The operation will be specifically described 'in extensions 2 and 22 connected to the contacts connection with a particular type of impregnated n and 13 respectively Transverse grooves 5 paper but it is to be understood that the invenand are provided along the lower edges of the is not restricted to paper. material Contact members n and 3 A Slot 2 is capable of being bent intoa tube could be used. Vided at the middle f the upper edge of the A sulphite paper that has been produced by the port 6, this slot being parallel to the anchoring Cold process after gent/1e grinding 50 as to means 1 and 8. A bearing 28 is anchored in the (111% Very thin p p f high te s le strength support 5 d has a longitudinal Opening 29 and uniform thickness is wound upon the perfotherethrough A corresponding opening 30 is rated mandrel 48 while the pressure Wiping or provided in t Support 5 which serves as a bean retarding friction roller 31 is kept, pressed against ing. A larger opening 3| extends from the openthe outer surface of the paper by the pressureing 30 to the outside of the support 6. An annup y members 35 a and is p h d lar shoulder 32 is provided between the openings y the Current from Secondary 49 f tra sformer 36 and 3|.

Screw bolts 33 and 34, Fig. 4, are anchored in holes in the upright members 5 and 6 a short distance from the openings 29 and 30. Pressureapplying members 35 and 36 are pivoted eccentri- 48. It has been found that sulphite paper known as Mitscherlich is particularly suited for this process. This is paper made by the sulphite cold process and well hydrated. Preparatory to being treated by the present process it is impregnated 3 with phenol-formaldehyde resin that is soluble either in water or alcohol or a mixture of the two. The percentage of the resin to paper may be from about 28% to about 40% with good results.

The operation of my device is as follows: The impregnated uncured paper is wound convolutely and tightly upon the mandrel 40 until sufficient layers are wound on to give the desired wall thickness. The paper is then laminated and the resin cured simultaneously by means of heat. The sheet of paper 56 is then cut transversely. The contact [8 is raised upwardly by pivoting on pivot 20, thereby freeing that end of the mandrel 40 so that it can be lifted out through slot 21 and the formed tube removed after the suetion hose is disconnected. The hose and mandrel are replaced and the operation is repeated to produce the next tube.

The pressure or wiping-rod 31 and pressure applying members 35 and 36 are desirable in that the same pressure is applied to all the tubes and hence their strength and other characteristics are uniform. However, for limited production or where absolute uniformity of characteristics is not particularly important, the retarding pressure against the sheets on the mandrel may be applied by hand. One method of accomplishing the desired result is to hold a piece of heavy felt or other flexible material by hand against the impregenated paper at one or more places along its length while the mandrel is rotating.

The base and upright members of my invention are shown as being made of wood. Other materials, such as metal, could be used, but insulating members would have to be inserted at appropriate places in the apparatus to prevent a short circuiting of the electrical connections.

One embodiment of my invention has been illustrated.

What I claim is: I

1. In a device for producing paper tubing, supporting members, one of said members having a slot therein, a mandrel, one end of the mandrel resting in said slot, said mandrel being hollow and provided with a series of perforations, a vacuum line connected to one end of said mandrel for applying suction to a sheet of paper, means for rotating said mandrel, means connected to said mandrel for conducting electricity to the mandrel in order to heat the same, one of said means being pivotally mounted so as to contact said mandrel in operating position and to permit removal of one side of the mandrel through the slot in the supporting member in open position.

2. In a device for producing paper tubing, supporting members, one of said members having a slot therein, a mandrel, one end of the mandrel resting in said slot, said mandrel being hollow and provided with a series of perforations, a vacuum line connected to one end of said mandrel for applying suction to a sheet of paper, means for rotating said mandrel, means connected to said mandrel for conducting electricity to the mandrel in order to the same, one of said means bein ivotally mounted so as to contact said mandrel in operating position and to permit removal of one side of the mandrel through the slot in the supporting member in open position, a pair of gravity weights eccentrically mounted on pivots, a pressure bar fixedly secured to said weights whereby a uniform constant pressure will be applied against the paper being wrapped on said mandrel.

3. In a device for producing paper tubing, supporting members, one of said members having a' slot therein, a mandrel, one end of the mandrel resting in said slot, said mandrel being hollow and provided with a series of perforations, a vacuum line connected to one end of said mandrel for applying suction to a sheet of paper, an electric motor for rotating said mandrel, electric contacts connected to said mandrel for forming an electrical path through said mandrel whereby the electricity will heat the same, means for pivotally mounting one of said contacts so that said contact will contact said mandrel in operating position and to permit removal of one side of the mandrel through the slot in the supporting memher in open position, said electric motor and said electric contacts connected to the same source of electricity, a pair of gravity weights eccentrically mounted on pivots, a pressure bar fixedly secured to said weights whereby a uniform constant pressure will be applied against the paper being wrapped on said mandrel.

4. The process of producing paper tubing which comprises feeding a sheet of phenol formaldehyde ir'ripre'gnated'sulphite paper to a mandrel, applying' suction to draw the paper toward the mandrel, heating the mandrel by passing electricity through the walls thereof to fuse and to set the resin in the paper, applying a movable, non-r0- tatable pressure bar over a small circumferential area at one time but throughout the length of the tube, rotating the mandrel, pivoting one of the electrical heating contacts, raising one end of the mandrel, and removing the finished tubing.

5. The process of producing paper tubing which comprises the steps of feeding resin impregnated paper to a cold mandrel, applying a vacuum to the mandrel, revolving the mandrel while applying the vacuum, wrapping the paper around the" mandrel by means of the vacuum, and rapidly heating the mandrel to set the resin and bond together thevariousplies of the tube.

6. The process of producing paper tubing which comprises the steps of feeding resin impregnated paper to a mandrel, revolving the mandrel while the paper is applied thereagainst, wrapping the paper around the mandrel while applying a retarding force manually, and applying a large current of electricity directly through the mandrel to set the resin in the paper and thereby bond together the various plies.

7. The process of producing paper tubing which comprises the steps of heating a hollow core, perforated mandrel by passing an electric current longitudinally directly through the mandrel, feeding resin impregnated paper to said mandrel, applying a vacuum to the entire irmer core of the mandrel, revolving the mandrel while applying the vacuum, and wrapping the paper around the mandrel by means of the vacuum at the same time that the resin impregnant is being made tacky by the heated mandrel.

8. The process as set forth in claim 7 in which the outer plies of the former paper tube will be made to overlie directly the inner plies by feeding the impregnated paper to a rotatable mandrel mounted on a fixed pivot.

9. The process'as set forth in claim 8 in which retarding pressure is applied to the plies of the tube as it is being wrapped so as to produce a tight, strong tube.

10. In a device for producing paper tubing, an electricity-conducting mandrel, means for revolving said mandrel around a permanently fixed axis to wrap a sheet of paper thereupon, an electric current source, and a pair of contacting means for connecting said current source to two points spaced along the length of said electricityconducting mandrel to thereby form a closed electrical circuit longitudinally therethrough so that said mandrel may be directly heated while being revolved.

11. In a device for producing paper tubing, a hollow electricity-conducting mandrel having perforations in the body thereof, means for revolving said mandrel around a permanently fixed axis to wrap a sheet of paper thereupon, means for applying suction to the interior of said hollow mandrel while said mandrel is being revolved, an electric current source, and a pair of contacting means for connecting said current source to two points spaced along the length of said electricityconducting mandrel to thereby form a closed electrical circuit longitudinally therethrough so that said mandrel may be directly heated while being revolved.

12. In a device for producing paper tubing, a hollow electricity-conducting mandrel having perforations in the body thereof, means for revolving said mandrel around a permanently fixed axis to wrap a sheet of paper thereupon, means for applying suction to the interior of said hollow mandrel while said mandrel is being revolved, pivoted gravity means biased toward engagement with said mandrel for applying wiping pressure to the paper being wrapped on said mandrel, an electric current source, and a pair of contacting means for connecting said current source to two points spaced along the length of said electricityconducting mandrel to thereby form a closed electrical circuit longitudinally therethrough so that said mandrel may be directly heated while being revolved.

CHARLES B. HEMMING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 157,970 Mottram Dec. 22, 1874 652,445 Skofsrud June 26, 1900 1,137,853 Fortesque May 4, 1915 1,569,656 Kehse Jan. 12, 1926 1,921,516 Frederick Aug. 8, 1933 2,250,430 Wade July 22, 1941 Certificate of Correction Patent N 0. 2,57 4,329 November 6, 1951 THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

